Casting with a six gang mold

[Leadmelter]

I tried out my MP 359-147 gr mold. I was having trouble getting all the cavities to fill out. With the sprue handle in place, it gives very little room to hold the mold handles. I try to hold them without exerting too much pressure. The nose of the bullet fills out but the bottom is hit or miss. I tried adjusting the lead flow and all that did was for one cavity to spill over into the next. I tried filling front to back and back to front no help. Pot is set at 730 F.
Leadmelter
MI

[Walter Laich]

is the mold up to temp?

I usually start by just filling one cavity, open, dump and then two cavities etc until I am filling all 6. Even then I have a run of 5-10 cycles to get the mold up to having the mold hot enough to get good bullets

I also set in on top of the pot as it heats up to cut down on time needed to bring mold up to temp.

brass molds take a bunch of heat to get up to temp and aluminum ones lose heat quickly so a lot of quick casting and dumping bullets at the beginning will help with getting temp up (most if not all of these bullets will be rejects)

[Cherokee]

Sounds like mold is not up to temp. I use a hot plate to preheat my mold and usually get keepers on the first run, 2, 4, 5 or 6 bangers.

[reddog81]

I've started using the MP 8 cavity mold and you definitely have to run them fast when starting. I use a hot plate but it only goes up to 300 degrees so the spruce plate really isn't hot when you start. I've got in the habit of starting off by just covering the spruce plate with lead the first couple of pours and only letting a little lead fall into the mold. This alllows for easy opening of the spruce plate and helps with fill out on the base of the bullet once you start casting.

When casting I hold the mold at a slight angle not allowing lead into the next cavity until you move the handle. I just do a continuous stream, at least when starting out, and try to get the mold up to temp ASAP.

[sigep1764]

I also use a continuous stream when filling a multi cavity mold. Pour heavy sprues to begin with to heat the sprue plate. As soon as that sprue is has gone from unmelted lead to somewhat solid, open and dump. Its gonna take a few pours to get it up to temp, but once it does the boolits will come out perfect and you can slow your cadence of pouring/opening/dumping/pouring/opening/dumping. You can tell if you are going too fast buy glancing at the top of the mold and underside of the sprue plate while opening and dumping. If there are lead smears, slow down the opening of the mold a few seconds. The sweet spot is good fillout and no smearing. You'll get a time count or a feel for the time needed. Every mold likes a different cadence. I have a Lyman iron 2 cavity that never seams to overheat or smear and Lee aluminum 2 cavity that likes it slower. My 4 cavity aluminum hollow point mold from NOE likes it fast to heat the pins then a good 5 count once its up to temp.

[Grmps]

" With the sprue handle in place, it gives very little room to hold the mold handles". not familiar with MP but Is the mold on backward?

I preheat on a hotplate with a 3/8 piece of steel on top.

I pressure pour (hold the mold up to the spout and fill each cavity then pull back for a second to get a puddle) the first 5 to 10 pours to help warm the mold and get a good fill

[Mal Paso]

I wouldn't run the 6 cavity without preheating on a hot plate. Cutting Cold sprues puts a lot of stress on the mold.

I have Lee handles on mine as the MP wouldn't open far enough to let the back bullet drop.

[mdi]

IMO; one thing "wrong" with gang molds is temp control. Often one end will get up to temp., but the other end may be too cold. BTDT. I now use a hotplate and give the mold plenty of time to reach casting temp...

[scotner]

And I thought I have made a big discovery when I bought my hotplate. Apparently this is common practice. I found a refurb Oster with some kind of rubbery (silicone?) mat on it. I place a couple of molds on it and turn it to medium heat when I start the lead pot and the molds are ready when the lead is. I always cull the first fill on each mold just in case but they usually look good from the first drop. That Lyman 6 cavity 45 is a monster and it always took forever to start dropping boolits if I just set it on top of the lead pot to pre warm. I have to put some blocks under the handles of the aluminum molds and the smaller iron molds to keep them flat on the hotplate surface but that big steel mold will set flat and hold the handles up.

[mdi]

A hint I read here; the "burner" of many hot plates is slightly dome shaped and to get good even heating/contact place an old 8" Skill Saw blade on the burner. It allows the mold to heat more evenly with more of the mold in contact with the blade...

[jsizemore]

I put my molds on the hot plate sprue plate down with the mold in the closed position. I usually have to wait a few minutes to use the mold after the element has cycled off.